Can you run 450i in single polarity?

Hi folks. Long time PMP100 900mhz owner here.

Can you run the 450i at either horizontal or vertical (but not both).

Or can you attach a seperate antenna for the H/V?

I am curious if I can reuse the hundreds of yagis I have.

Is this even worth messing with?

No you can't i asked cambium the same question. You must buy the newer yagi for it to work. KP performance also has new yagi antennas. And new panels for 450I stuff. 

In places where aesthetics weren't a big issue, we have been using two single polarity yagis, one each for +45° and -45°, stacked about 18" apart.  Those links have been working great.